Carl, your problem sounds very familiar to me, but I'm not really sure
if it is quite the same as the problem I once had. I had a fairly
complex use-case that involved summarising multiple values from multiple
document types, being able to search for these by date (in my case
[year, month] or [year, week_nbr]). So my map/reduce has so much going
on, I'm not sure the heart of the issue is really same as yours or not.
I've done my best to distill this down to your use-case... but there's
one glaring issue in that my function wants to use the country name as a
key, and your country names contain spaces, which won't work as keys.
So, I'm going to assume that they're 2-letter country codes instead.
Also, I'm sure someone might say that I'm abusing the reduce function...
there might be a simpler way of doing this with just one value to be summed.
map:
{
var obj = {};
obj[doc.country] = 1;
emit ([date], obj)
}
reduce:
{
var sums = {};
for (var i in values)
for (var k in values[i])
sums[k] = (sums[k] || 0) + values[i][k];
return sums;
}
You can query using startkey,endkeys corresponding to the date range,
and if you set group_level=0 in your query, you should end up with
something like this:
{"key":null, "value":{ UK:3, DE:1, HU:1, FR:2, US:1 }}
Which of course isn't quite the structure you might have been hoping
for... but it does give the right answer in a single row.
On 06/10/2012 23:12, Carl Bourne wrote:
Yes - exactly!
Which was why I was hoping the reduce function would help. I have managed to do
this using some additional middleware (Ruby Sinatra), but that seems to defeat
the purpose of using something like Couch in the first place!
Carl Bourne | Senior Sales Engineer | mobile: +44 (0) 7770 284294 |
www.venafi.com
On 6 Oct 2012, at 21:58, Aurélien Bénel <[email protected]> wrote:
I still not understand why you need to count the docs with the same exact
timestamp
Ah I think I understand now... You want to select by (exact) date but group by
countries.
Hmm, then it's not hierarchical, you have two different dimensions. Then my
solution cannot help you. Sorry.
Regards,
Aurélien
